<template>
  <div id="root">
    <div class="todo-container">
      <div class="todo-wrap">
        <Header :addTodo="addTodo"/>
        <List :todos="todos" :deleteTodo="deleteTodo" :checkOne="checkOne"/>
        <Footer 
					:todos="todos" 
					v-if="todos.length" 
					:checkAll="checkAll" 
					:deleteAllDoneTodo="deleteAllDoneTodo"
				/>
      </div>
    </div>
  </div>
</template>

<script>
	import Header from './components/Header.vue'
	import List from './components/List.vue'
	import Footer from './components/Footer.vue'

	export default {
		name: "App",
		components:{Header,List,Footer},
		data() {
			return {
				todos:JSON.parse(localStorage.getItem('todos')) || []
			}
		},
		methods: {
			// 用于向todos数组中添加一个todo对象
			addTodo(todo){
				this.todos.unshift(todo)
			},
			// 用于在todos数组中删除一个todo对象
			deleteTodo(id){
				//第一种方式
				/* this.todos = this.todos.filter((todo)=>{
					return todo.id !== id
				}) */

				// 第二种方式
				// 找到要删除项的索引值
				let index = this.todos.findIndex( todo => todo.id === id )
				// 操作数组
				this.todos.splice(index,1)
			},
			// 用于全选todos
			checkAll(done){
				this.todos.forEach((todo)=>{
					todo.done = done
				})
			},
			// 用于在todos数组中清除所有已完成的
			deleteAllDoneTodo(){
				this.todos = this.todos.filter((todo)=>{
					return todo.done === false
				})
			},
			// 用于在todos数组中勾选某个todo对象
			checkOne(id,flag){
				let result = this.todos.find((todo)=>{
					return todo.id === id
				})
				result.done = flag
			}
		},
		watch:{
			// 深度监视todos，哪怕todos里的某一项的某一个属性，有一点点变化，都能监视到
			todos:{
				deep:true,
				handler(value){
					localStorage.setItem('todos',JSON.stringify(value))
				}
			}
		}
	};
</script>

<style>
/*base*/
body {
  background: #fff;
}

.btn {
  display: inline-block;
  padding: 4px 12px;
  margin-bottom: 0;
  font-size: 14px;
  line-height: 20px;
  text-align: center;
  vertical-align: middle;
  cursor: pointer;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2),
    0 1px 2px rgba(0, 0, 0, 0.05);
  border-radius: 4px;
}

.btn-danger {
  color: #fff;
  background-color: #da4f49;
  border: 1px solid #bd362f;
}

.btn-danger:hover {
  color: #fff;
  background-color: #bd362f;
}

.btn:focus {
  outline: none;
}

.todo-container {
  width: 600px;
  margin: 0 auto;
}
.todo-container .todo-wrap {
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 5px;
}
</style>